Everything goes perfectly smooth until last Friday, i saw some errors: Error creating csv/xls file. I then went thru the program to see if i could replicate the issue, unfortunately it runs all good when I tried the same functions on my own. So I added a log to see what's the actual error was, turns out to be : Cannot copy the file to "Your List", it's been accessed by another user. Well since it runs overnight, and no one is using the file at all times, I can only assume this is caused by trying to copying the file before the Deleting process has finished.
Well this does happen and a lot on network file copying/deleting.
I tried to give a delay between deleting and copying, well it does help a little, but it's not always a good idea as error will still come at some stage.
In my case, I changed the file name to add either customer name or supplier name, which make those files all different, and fixed the problem. Although it'll be better to know an alternative way of solving the issue without changing the name.